The present inventive concept herein relates to a slurry for polishing and a planarization method of an insulating layer using the same.
A chemical mechanical polishing (hereinafter, referred to as CMP) process is a planarization process for flattening a surface of a wafer or a semiconductor substrate during fabrication of a semiconductor device. The CMP process may include a mechanical etching process and a chemical etching process. The chemical etching process and the mechanical etching process may be performed using a slurry provided between the wafer and a polishing pad. A type of slurry for polishing may be determined in accordance with a material layer to be polished. For example, in the CMP process of a silicon oxide layer, a silica-based slurry (hereinafter, also referred to as a silica slurry) or a ceria-based slurry (hereinafter, also referred to as a ceria slurry) may be used to flatten a surface of the oxide layer. The silica slurry includes silica particles as an abrasive, and the ceria slurry includes ceria particles as an abrasive. The silica slurry is mainly used to remove a step difference of a silicon oxide layer. When the silica is used in the CMP process, byproducts may adhere to and remain on a surface of a polishing pad even after the CMP process is finished. The byproducts generated by the silica slurry may cause scratches on the surface of a wafer or a substrate. The ceria slurry is widely used to polish a flat silicon oxide layer.